1. Field of the Invention
The invention relates to the working end of a micro-catheter or other device for endoluminal introduction that utilizes a thermal energy emitter to apply energy to a fluid media within at least one interior bore of the working end to vaporize and/or cavitate the fluid and to eject the fluid media from the working end to apply energy to endoluminal structure in the form of therapeutic heat and/or acoustic energy.
2. Description of the Related Art
Varicose and spider veins are enlarged, dilated, and tortuous veins that are caused by weakness in the vein walls and incompetent vein valves. When the valves cease to function, the blood does not flow as effectively to the heart as it should but, rather, allowed to pool in the veins. This increases pressure in the vein and eventually causes the vessel walls stretch and distend. The vein increases in diameter and cannot return to normal size or shape.
In the prior art, catheter devices are used to apply radio frequency energy to vessel walls to cause ohmic heating therein which can damage and occlude the vessel. One disadvantage of commercially available Rf devices is that ohmic heating can easily damage nerves in the leg that extend along the exterior of varicose veins. New instruments and methods of energy delivery are needed for closure of blood vessels to treat varicose veins.
In the treatment of thrombus in a blood vessel, either in cardiac patients or stroke victims, conventional treatment is the intravenous administration of pharmacologic agents, such as t-PA (tissue plasminogen activator), streptokinase or urokinase. In such intravenous drug deliveries, the probability of success may be less than about 50 percent, and the success rates are limited by the fact that agents are not delivered directly to the site of the thrombus. To ablate thrombus in an invasive procedure, various energy-based catheters have been developed, for example utilizing laser and ultrasound energy delivery systems. A disadvantage of such approaches is that the catheter's diameter may be too large, and the catheter's flexibility may be limited, thus preventing the catheter's working end from reaching the thrombus site in the small circulatory arteries of the patient's brain. New catheters and methods of energy delivery are needed for disrupting thrombus.